The present invention relates to a water pump and more particularly to a self-lubricating water-cooled piston-type water pump for use with carpet cleaning machines.
Piston or plunger-style water pumps used in carpet cleaning machines are well known. However, all such known pumps used in carpet cleaning machines are known to be lubricated with grease or heavy lubricant being applied to the components within the crankcase including the crankshaft, connecting rods, and the piston or plunger rods to ensure long life of the moving parts within the pump and to prevent premature wear.
Generally there are two types of pumps. The first type commonly used in hydraulics consists of a motor rotating a radially-set group of veins in a turbine-like assembly. Often these types of pumps include the electric motor within the pump housing and they are generally very complicated. Another type of pump structure is the piston cylinder arrangement with a crankcase having the piston disposed within the cylinder and reciprocating therein to create pressure and work with one-way valves.
Both of these general types of pumps have tried to cool and lubricate their moving parts with the fluid that is being pumped or compressed. However, such arrangements inclusive with motors are terribly complicated and subject to common failure.
The cooling of the piston pumps has been problematic in that they are generally cooled by the incoming and outgoing water to be pumped or by an external fan adjacent the pump housing. No water in these types of pumps enters into the crankcase to bathe its moving parts.
These cooling methods lead to premature wear of the moving parts due to the heat they generate during operation. Occasionally, bearings or seals in these prior known pumps fail and compressed water will leak into the crankcase. This pump breakdown leads to soiled water and grease leaking out of the pump and carpet cleaning machine onto the newly washed carpets creating a serious stain, which sometimes becomes indelible.
There is a need for a greaseless self-lubricating water-cooled water pump for a carpet cleaning machine that is simple in structure, long-lasting and will not detrimentally stain its surroundings should a seal break during operation.